if you want to look at someone's hands while playing for example, you can add SLOW after youtube in the youtube video link, so it becomes youtubeSLOW.com/watch?..... and the page will let you slow down videos and play them in slow motion Slow down youtube video

I use http://www.keepvid.com/ to download YouTube videos as mp4 files. I then play them at half speed in QuickTime without changing pitch. The sound quality is very good, even at half speed. Note: in using keepvid be sure to click the "download" button that is right next to the space for entering the YouTube link. There are other "fake" download buttons that take you to advertisers' sites.

Hey, I'm a few years late to the party on this, but anybody who's still interested in slowing down YouTube videos should check out Soundslice (http://www.soundslice.com).

This is a site that lets you slow down YouTube videos and loop sections of them, with an emphasis on learning music.

It's super new and still a work in progress (I'm the guy who made it), but I'm improving it daily. Click one of the demos to see it in action, then search for anything in the search box on that subsequent page.

Adrian

I know several who use this method to visually transcribe (though you certainly good aurally) works. The speed adjustment tool - and really just video player altogether - is very good and the best I know.


edit: ah, just saw the original post date

OH MY!!!! This is SO perfect! I was JUST complaining the other day about how when I wanted to see how a particular part in a piece was played, it was always to fast!!

THIS. IS. GREAT.

If you're using Windows 8, try Media Player Plus (available from the App Store) - you can open YouTube videos (and local audio/video files), the slow them down (or speed them up if needed) without changing pitch.

Hope this helps.